This invention relates generally to automatic or semiautomatic, pneumatically-fired guns, and more particularly to paint ball guns.
Paint ball guns generally comprise a body with a hand grip, a barrel mounted on the body through which a paint ball is propelled, a magazine of projectiles feeding into the barrel, a trigger on a trigger plate, a sear retaining the striker in a cocked position by the trigger plate, and a source of compressed gas with a valve regulating compressed gas into the barrel. A spring-powered hammer and valve pin moves forward under spring bias during firing to impact and move a valve cup seal forward. As the valve cup seal moves forward, a body chamber filed with compressed gas opens to a bolt chamber and barrel attached thereto. A bolt moves linearly in the bolt chamber from a cocked position in which the magazine is unblocked forward to a firing position that pneumatically seals the barrel/bolt chamber from the magazine as compressed gas is received into the barrel/bolt chamber to expel a projectile from the gun.
For an automatic or semiautomatic gun the valve is three-way to also direct compressed gas to move the striker to a cocked position ready for next firing. As the trigger is further pulled past release of the sear, the timing rod acts through a mechanical assembly to direct gas through with the three-way valve to a ram that pushes the hammer and bolt rearward to the cocked position, reengaging the sear at the trigger in preparation for a next firing. Typically, the mechanical assembly comprises a threaded timing rod connected between the timing rod and a coupler at the three-way valve adjustable on its threads at the coupler to achieve correct timing.
The effective length of the timing rod is precise to assure that gas is released at only the appropriate time to recock the gun. If the timing rod is set improperly, the gun cocks at the wrong time relative to the firing sequence, or not at all, and the gun fails to operate.
The timing rod is generally a rod external to the gun body with a hooked end entering the body near the trigger to engage a hole in the trigger plate. Threads on its other end engage the three-way valve at the valve coupler external to the body by threading the rod into a coupler threaded hole. Thus, the timing rod alongside the gun body and trigger plate extends to the coupler threaded hole offset from a line between the trigger plate and the coupler threaded hole. A small torque is therefore generated through the timing rod between the trigger plate and the coupler that can affect the aim of the gun. Further, after repeated use, the timing rod tends to move on its threads in the coupler, changing its effective length and consequently the gun timing. As a result, the gun requires servicing to reset the rod in the coupler threads to an appropriate effective length. And in the meantime, the gun remains out of proper timing, though it may continue to function in less than optimum adjustment.
It is an object of the invention to provide a mechanism that circumvents the heretofore inherent mistiming, or at least eventual mistiming, of this type of gun. It is a further object to eliminate any torques between the trigger and the three-way valve that might alter gun timing or misaim the gun during firing. It is also an object to stabilize the gun with a vertical alignment of primary moving parts.
Because the trigger plate is within the gun body, and the valve coupler and three-way valve are mounted forward on the body, traditionally a timing plate is mounted external to the gun body off-axis from the trigger plate and the three-way valve, hooked on each end to connected to the trigger plate and coupler, respectively. This off-axis hooked rod causes a torque to be generated between the trigger plate and hooked rod and also between the hooked rod and the coupler, both of which cause the gun to misaim upon pulling the trigger. These torques are eliminated by connecting the trigger plate to the valve coupler with a timing plate within a groove in the gun body in straight alignment, resulting in the timing plate, trigger plate and coupler moving together in alignment on a single straight line. Thus, the gun body has a new timing plate groove opening at the trigger plate on one end and the coupler on the other end, thus eliminating the external timing plate that created the unwanted torques. The timing plate is connected to the trigger plate with a lug in a notch to avoid a solid connection that could transmit trigger plate torques to the timing plate. Because the timing plate moves entirely within the body failures due damage to the external timing plate and due also to dirt getting in the timing plate that preventing it from reliably sliding are eliminated.
Primary components of the gun comprise an upper bore in the gun body that includes the barrel and the bolt chamber. A projectile mounts on top of the gun body and feeds projectiles, frangible paint balls, into the bolt chamber. Below the upper bore is a second bore that includes a hammer chamber rearward of an air chamber. The hammer chamber encloses a hammer that strikes a valve cup seal between the hammer chamber and the air chamber, allowing pressurized gas to release from the air chamber through a passage to the bolt chamber and into a bolt passage through the bolt exhausting forward of the bolt to propel the paint ball in front of the bolt. Below the second bore is a third bore running from the gun front to the trigger plate low in the gun body. (Although the gun is characteristically constructed with a handle frame screwed onto a body block, for ease of description herein, the gun body is deemed to include both the body block and the handle frame.) In the third bore is a reciprocating timing plate aligned between the trigger plate and a three way valve that directs compressed air to automatically recock the gun. To provide improved balance and minimize internal torques during firing that can cause misaiming of the gun, the three boresxe2x80x94the bolt chamber, the hammer and air chamber chambers, and the timing plate groovexe2x80x94are arranged in vertical alignment in a plane defined by the movement of the trigger plate.